Dark dark matter is an invisible sea in which galaxies float. Vera Rubin noticed they spin too fast, as if an unseen weight tugs at the edges. Recently, physicists figured out how to catch the spray of this sea.

Beyond Pluto, icy asteroids and comets swarm. An impact with a clump of dark matter creates a tiny, scorching disk — a brilliant flash. A telescope could spot it.

If the sea consists of ultralight axions, particles a billion billion times lighter than an electron, space is riddled with their waves. These waves slightly alter fundamental constants, as Paul Dirac foresaw. Atomic clocks then tick faster and slower.

A massive clump bends light like a lens. This gravitational lensing effect was proposed by Fritz Zwicky. A star in the sky shifts.

Three methods catch different traces of the invisible. At least one will crack the mystery.